[Asterisk-bsd] Problem with ISDN / i4b and Asterisk

[Michael Landin Hostbaek]

Hello,

I have a FreeBSD box (6.2) running Asterisk 1.4 (latest from ports) -  
in it, I have a Digium B410P QuadBRI card. On the card, I have (at  
this time) one ISDN2 (T0) plugged in.

I have installed i4b (from trunk) with matching capi_chan.

On the other side of my Asterisk box I have a simple LAN with n SIP  
peers (typically Cisco 7940/7960 phones)

All SIP peers can ring back and forth without any problems, and they  
can of course, also ring to and from the Asterisk box (echo test,  
Voicemail etc etc)

Now, when I receive a call one ISDN line - I have setup the following  
dialplan:

[isdn-in]
exten => _4215,1,Goto(some_context,2000,1)

The SIP peer (2000) rings as expected, but the incoming sound quality  
it horrible, and there are huge delays. However, the outgoing RTP  
traffic is perfect.

I am ONLY having this problem with the Cisco phones.. when putting  
fx. X-Lite or a Siemens phone - everything works fine.

I have tried with different Cisco phones, and different firmware  
versions - but the problem persists.

It is the exact same problem when dialing out thru the ISDN lines.

The only thing I can see on the Cisco phones (stats) is that the  
"RxDisc" counter goes ballistic when it is connected.

Any ideas or suggestions would be much appreciated!!

/mich